The Nutritional Value of Pasta

the nutritionist’s opinion

Carlo Cannella, Alessandro Pinto

Institute of Food Science and Nutrition

“La Sapienza” University, Rome, Italy

Function of carbohydrates

An adult subject needs about 180 g/die of glucose to meet nervous system and erythrocytes energy requirements

Essentiality Necessity

Carbohydrates are necessary but not essential nutrients because the human body

can produce glucose from aminoacids (gluconeogenesis)

In a low carbohydrate diet, when the catabolism of glucose is active, acetyl-CoA from lipids is burned

otherwise it accumulates to form ketone bodies/fatty acids

Carbohydrate: classification

Simple Complex

Available or not available

Starch

Starch consists of linked glucose units arranged in either

straight or branched chains

Amylose

straight-chain form of starch based on several hundred glucose residues linked

by alpha-glucosidic bonds between carbons 1 and 4 of adjacent glucose

molecules

Amylopectin

branched-chain component of starch based on straight-chain form plus side-branches (by additional bonds between carbons 1 and 6 of two adjacent glucose

molecules)

Metabolic Pathway

Glucose and other absorbed monosaccharydes (fructose, galactose and mannose) are isomerised

and phosphorilated to glucose-6-P

Bloodglucose

Hepatic and muscleglycogen

CO2 + H2O + ATP Pentose phosphate Adipose tissue

Blood glucose control

blood glucose - normal range 110 mg/dl

70 mg/dl

glucose uptaken into cells glycogenosynthesis

Release of Insulinfrom pancreas

High levels ofblood glucose

breakdown of glycogen increase of gluconeogenesis

Release of Glucagonfrom pancreas

Low level ofblood glucose

Glucose Amount from different sources

100 g bread 80 g pasta 60 g sugar

They cause different glucaemia increase rates

G.I. “glycaemic index”

Glycaemic index

It is possible to measure the relative effects of different carbohydrate foods on the blood sugar level. The rise in blood glucose following ingestion of a portion of a test food containing 50 g of

available carbohydrate is compared with the effect on blood glucose of a 50 g available carbohydrate portion of a standard such as glucose or white bread. Comparison of the areas under

the two glucose curves obtained produces a “glycaemic index”

Glycaemic Load = GI x dietary carbohydrate content

Its glycaemic index is suitable for achievements of daily quota of carbohydrates (50-60% total energy uptake)

Its association with different sauces improves nutritional value of proteins (cheese) and exerts an anticancer activity (tomato and onion)

It has a reduced fat content especially of saturated fatty acids and an important source of fiber (affecting other nutrient absorption)

…… but remember portion size of 80 g!

Scientific evidences support pasta daily consumption